On the final leg of his visit to the United States, Pope Francis spoke in Philadelphia about the importance of women within the Catholic Church.

The pontiff celebrated a mass in the Cathedral Basilica of Sts. Peter and Paul with 1,600 people, and said the futire of the Church in the US depends on more active lay membership, especially among women.

"It means valuing the immense contribution which women, lay and religious, have made and continue to make to the life of our communities," he said.

He did not however, call for the ordination of women, which he has opposed in the past.

He is expected to attract an audience of over one million people at his final appearance in Philadelphia tomorrow.

During his earlier visit to New York, huge crowds gathered in Central Park to see him yesterday - especially at Ground Zero.

The pontiff also held a special mass for thousands at Madison Square Garden last night.

He told the crowd that, "living in a big city is not always easy. A multicultural context presents many complex challenges. Yet big cities are a reminder of the hidden riches present in our world: in the diversity of its cultures, traditions and historical experiences. In the variety of its languages, costumes and cuisine.

"Big cities bring together all the different ways which we human beings have discovered to express the meaning of life, wherever we may be," he added.

These people were among the crowd of 20,000 people at the mass:

Meanwhile, Pope Francis has sent a special message to those attending the National Eucharistic Congress which opens this morning in Knock, County Mayo.

Thousands are expected to attend the two-day celebration of faith on the theme of Christ Our Hope.

Pope Francis says he wants pilgrims to seek to build a world that is ever more just.